The objective of this investigation is to experimentally study the effect of withdrawal from smoking on a variety of behaviors, and changes in these behaviors with sustained abstinence. Behavioral toxicological methods including advanced computerized assessment techniques will be used to evaluate both immediate (0-48 hours) and long-term (to 6 months) post-withdrawal changes in certain sensory, motor, psychomotor, cognitive, and emotional responses of young university students and personnel. These data will then be compared with changes in the field performance of these and other individuals who have recently ceased smoking. The underlying rationale for this study is that the results would help to resolve questions regarding the nature and magnitude of behavioral components of the smoking withdrawal syndrome, whether or not they are reflected in daily activity or occupational performance changes, and whether or not they are of sufficient magnitude to warrant serious consideration or precautionary procedures in behavioral toxicological and human performance studies as well as smoking cessation programs.